Emergency lighting circuit and lighting system

Abstract

The present application discloses a control scheme for emergency lighting, wherein an AC input voltage supplies power to a lighting load through a power supply device, the power supply device including a voltage conversion circuit and a battery, the voltage conversion circuit receives the AC input voltage to supply power to the lighting and charge the battery, and when there is no AC input voltage, when the emergency lighting needs to remain illuminated, the emergency lighting is supplied with power through the battery, and a discharge circuit is connected to at least one input end of the AC input voltage to discharge the voltage at the AC input end. The present application discharges the voltage at the AC input end in the discharge circuit, so that the system can accurately determine whether there is an AC input, so as to control the internal battery to start the emergency lighting, and ensure that the emergency lighting is turned on smoothly in some specific occasions.

Description

Technical Field

[0001] The present invention relates to the technical field of power electronics, and more particularly to an emergency lighting circuit and a lighting system. Background Art

[0002] In the emergency lighting system, there are two circuits for supplying power to light source loads such as LED lamps. One circuit is for AC input to directly supply power to the load through a switch converter, and the other circuit is for emergency battery to supply power to the load. In the case of normal AC input, the AC input is converted into a suitable voltage to supply the load through a switch converter such as an ACDC converter; in the case of no AC input, if the impedance of the two input terminals L / N is less than a preset value, the load is powered by the emergency battery, and if it is greater than the preset value, the lighting system is turned off.

[0003] However, in environments with fans or elevators, the input impedance may be misdetected. This is because a large generator will cause the switch at the L / N terminal to be disconnected, that is, when there is no input AC, there will still be residual AC voltage. The residual voltage will cause the input terminal to misdetect that there is AC input. At this time, the emergency lighting cannot be turned on, resulting in the load not being able to work.

[0004] Therefore, it is necessary to provide an improved technical solution to overcome the above technical problems existing in the prior art. Summary of the invention

[0005] In view of this, an object of the present invention is to provide an emergency lighting circuit and a lighting system to solve the technical problem of false detection in some environments existing in the prior art.

[0006] The present invention provides an emergency lighting circuit, wherein an AC input voltage supplies power to a lighting load through a power supply device, including: the power supply device includes a voltage conversion circuit and a battery, the voltage conversion circuit receives the AC input voltage to supply power to the lighting lamp and charges the battery, and an emergency lighting control circuit, in the absence of an AC input voltage, when the emergency lighting lamp needs to maintain lighting, the emergency lighting control circuit controls the battery to supply power to the emergency lighting lamp, the lighting load includes the lighting lamp and the emergency lighting lamp, wherein the emergency lighting control circuit includes a discharge circuit, the discharge circuit is connected to the input end of the AC input voltage or the end point of the lighting load to discharge the voltage of the connection node so that the emergency lighting control circuit can determine whether there is an AC input voltage.

[0007] Preferably, the discharge circuit discharges the voltage at the AC input end with a predetermined current.

[0008] Preferably, the discharge circuit is connected to at least one input terminal of the AC input voltage to discharge the voltage of the AC input terminal.

[0009] Preferably, the emergency lighting control circuit includes an AC input detection circuit, which is connected to an input terminal of the AC input to obtain an input detection signal, and compares the input detection signal with a first threshold voltage. When the input detection signal is lower than the first threshold voltage, the discharge circuit is controlled to discharge the voltage of the AC input terminal.

[0010] Preferably, when the input detection signal is higher than the first threshold voltage, the discharge circuit is controlled to stop discharging the voltage at the AC input end, and after a delay of a period of time, a timer is started to count, and when the input detection signal is lower than the first threshold voltage or the timer reaches a preset value, the discharge circuit is controlled to discharge the voltage at the AC input end.

[0011] Preferably, the discharge circuit comprises a first discharge circuit and a second discharge circuit, the first discharge circuit is connected to one input end of the AC input voltage, and the second discharge circuit is connected to the other input end of the AC input voltage.

[0012] Preferably, the first discharge circuit includes any one of a switch tube, a resistor and a switch tube connected in series, or a switch tube and a current source connected in series; the second discharge circuit includes any one of a switch tube, a resistor and a switch tube connected in series, or a switch tube and a current source connected in series.

[0013] Preferably, the first discharge circuit includes any one of a resistor and a current source; and the second discharge circuit includes any one of a resistor and a current source.

[0014] Preferably, the power supply device also includes a high-voltage isolation circuit, and the emergency lighting control circuit includes an impedance detection circuit. The high-voltage isolation circuit is connected between the AC input terminal and the battery. When there is AC input, it is used to isolate the AC input terminal and the battery. The impedance detection circuit is used to detect the impedance of the two AC input terminals to generate an impedance detection result. When there is no AC input voltage, the emergency lighting control circuit determines whether to start the battery to supply power to the emergency lighting lamp according to the impedance detection result.

[0015] Preferably, the impedance detection circuit obtains an input detection signal based on an input terminal connected to the AC input, and compares the input detection signal with a second threshold voltage to obtain the impedance detection result. The emergency lighting control circuit includes a switch control circuit and a first switch tube. The switch control circuit receives the comparison result of the AC input detection circuit and the impedance detection result. When both are in a valid state, the first switch tube is controlled to be turned on so that the battery can power the lighting lamp.

[0016] Preferably, the discharge circuit is connected to the endpoint of the lighting load to discharge the connection node voltage. The emergency lighting control circuit includes an impedance detection circuit, a comparison circuit, a switch control circuit and a first switch tube. The impedance detection circuit obtains an input detection signal according to an input terminal connected to the AC input, and compares the input detection signal with a second threshold voltage to obtain the impedance detection result. The comparison circuit compares the connection node voltage between the discharge circuit and the lighting load and a reference voltage to obtain a comparison signal. The switch control circuit receives the comparison result of the comparison signal and the impedance detection result. When both are in a valid state, the first switch tube is controlled to be turned on so that the battery can power the lighting lamp.

[0017] In a second aspect, a lighting system is provided, comprising the above-mentioned emergency lighting circuit and a lighting load, wherein the emergency lighting circuit receives an AC input voltage to control normal lighting and emergency lighting of the lighting load.

[0018] The control scheme of the emergency lighting of the present invention discharges the residual voltage at the AC input end or the terminal voltage of the lighting load in the discharge circuit, so that the system can accurately determine whether there is AC input. In the absence of AC input, the emergency lighting is started by the built-in battery, ensuring that the emergency lighting can be turned on smoothly in some specific occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a circuit block diagram of a first embodiment of an emergency lighting circuit according to the present invention;

[0020] Figure 2 is a circuit block diagram of a second embodiment of an emergency lighting circuit according to the present invention;

[0021] Figure 3 is a circuit block diagram of a third embodiment of an emergency lighting circuit according to the present invention;

[0022] Figure 4 Based on Figure 2 Specific circuit diagram of the embodiment;

[0023] Figure 5 Based on Figure 2 Specific circuit diagram of the AC input detection circuit, impedance detection circuit and switch control circuit of the embodiment;

[0024] Figure 6 Based on Figure 3 A specific circuit diagram of a discharge control unit of an embodiment;

[0025] Figure 7 A circuit diagram of a first embodiment of a discharge circuit;

[0026] Figure 8 A circuit diagram of a second embodiment of a discharge circuit;

[0027] Fig. 9 A circuit diagram of a third embodiment of a discharge circuit. DETAILED DESCRIPTION

[0028] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, but the present invention is not limited to these embodiments. The present invention covers any substitution, modification, equivalent method and scheme made within the spirit and scope of the present invention.

[0029] In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without these detailed descriptions.

[0030] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. It should be noted that the accompanying drawings are all simplified and not in exact proportion, and are only used for the purpose of conveniently and clearly assisting in explaining the embodiments of the present invention.

[0031] refer to Figure 1The circuit block diagram of the first embodiment of the emergency lighting circuit of the present invention is shown in the figure. The emergency lighting circuit of the present application is applied in the lighting system. The AC input voltage supplies power to the lighting load through the power supply device. The power supply device includes a voltage conversion circuit and a battery. The voltage conversion circuit receives the AC input voltage to supply power to the lighting lamp and charge the battery. The voltage conversion circuit takes an ACDC converter as an example. In the case of AC input voltage or no AC input voltage, the AC input voltage is converted into a desired DC power supply to supply power to the lighting lamp through the ACDC converter. In the case of no AC input voltage, when the emergency lighting lamp needs to maintain lighting, the emergency lighting control circuit controls the battery to supply power to the emergency lighting lamp. The lighting load includes the lighting lamp and the emergency lighting lamp. The emergency lighting lamp can be part of the lighting lamp or another lighting lamp load. The emergency lighting control circuit includes a discharge circuit. In this example, the discharge circuit is connected to at least one input terminal of the AC input voltage to discharge the voltage of the AC input terminal. Here, the discharge circuit can be one discharge circuit connected to one input terminal; or two discharge circuits connected to two input terminals for discharge. The voltage conversion circuit may include a rectifier current to rectify the AC input voltage to obtain an input DC voltage. The voltage conversion circuit may be configured to supply the DC input voltage to a battery for charging through a switch, or to couple the voltage to the battery for charging through a winding, or to supply the voltage at the output end to the battery for charging.

[0032] Figure 1 Take a discharge circuit as an example. Figure 2 This is a circuit block diagram of a second embodiment of an emergency lighting circuit according to the present invention; taking two discharge circuits as an example, the discharge circuit includes a first discharge circuit and a second discharge circuit, the first discharge circuit is connected to one input end of the AC input voltage, and the second discharge circuit is connected to the other input end of the AC input voltage.

[0033] Preferably, the discharge circuit discharges the voltage of the AC input terminal with a predetermined current. For example, the discharge circuit discharges the voltage of the AC input terminal with a constant current, or it can discharge the voltage of the AC input terminal with a variable current. The value of the predetermined current is generally set to a smaller value to avoid excessive power consumption.

[0034] refer to Figure 4 for Figure 2 Specific circuit diagram of the embodiment in Figure 5 Based on Figure 2 Specific circuit diagram of the AC input detection circuit, impedance detection circuit and switch control circuit of the embodiment, Figure 6 Based on Figure 3 The specific circuit diagram of the discharge control unit of the embodiment. Figure 4 and Figure 5, the discharge control unit controls the discharge on and off of the discharge circuit, and the discharge control unit is connected to the input voltage detection circuit. Here, the emergency lighting control circuit includes an AC input detection circuit, and the AC input detection circuit includes a detection circuit (resistors R1 and R2) and a comparator U1, Rd is the equivalent resistance between the two input terminals, and the detection circuit is connected to one input terminal of the AC input voltage to obtain an input detection signal, and compares the input detection signal with the first threshold voltage Vref1. When the input detection signal is less than the first threshold voltage Vref1, the comparison result Vu1 output by the comparator U1 is a high-level effective state, and the discharge control unit starts the discharge circuit to discharge according to the comparison result of the comparator U1. When the input detection signal is greater than the first threshold voltage Vref1, the comparison result Vu1 is a low-level effective state, and the discharge control unit turns off the discharge circuit, and at this time, after a delay, a timer, such as timer 2, starts timing, and when the input detection signal is lower than the first threshold voltage or the timer reaches, the discharge circuit is controlled to discharge the voltage of the AC input terminal. In this way, the preset value of timer 2 lasts for a period of time that is less than or equal to half of the power frequency cycle, which is known to those skilled in the art. Figure 6 The discharge control unit receives the comparison result Vu1 and the negative signal of the comparison result Vu1. The negative signal of the comparison result Vu1 obtains the start time of the timer after a delay, and the negative signal of the comparison result Vu1 resets the previous count of the timer. The comparison result Vu1 and the signal of the timer 2 are passed through the OR gate to obtain a signal for controlling the discharge circuit.

[0035] refer to Figure 7 , Figure 8 and Fig. 9 The discharge circuit may include a first discharge circuit or a first discharge circuit and a second discharge circuit. The first discharge circuit includes a switch tube, a resistor and a switch tube in series, such as a switch tube Q1 and a resistor R3, or a switch tube and a current source in series; the second discharge circuit includes a switch tube, a resistor and a switch tube in series, such as a switch tube Q2 and a resistor R4, or a switch tube and a current source in series. Here, the discharge condition of the discharge circuit, such as the discharge time and the discharge duration, is controlled by the switch tube, so that the discharge can be better controlled. The switch tube can control the switch state according to the comparison result of the input voltage detection. Reference Fig. 9 The first discharge circuit includes any one of a resistor and a current source, such as current source I1; the second discharge circuit includes any one of a resistor and a current source I2. Those skilled in the art will appreciate that the above discharge circuits can discharge the voltage at the input terminal with a predetermined current.

[0036] Continue to refer Figure 5, the power supply device also includes an impedance detection circuit, a high-voltage isolation circuit and a switch module, the switch module includes a switch control circuit and a first switch tube S1, the impedance detection circuit includes a comparator U2 for detecting the impedance of the two AC input terminals to generate an impedance detection result, the impedance detection circuit obtains an input detection signal according to one input terminal connected to the AC input, and compares the input detection signal with the second threshold voltage Vref2 to obtain the impedance detection result Vu2. Here, the AC input detection circuit also includes a timer 1. When the timer 1 receives the comparison result of the comparator U1 and continues to be in a low-level invalid state for a period of time, it determines that there is no input AC voltage. The negative signal of the comparator U1 is used to reset the timer 1, and the timer 1 outputs a signal Vj to the switch control circuit. When the switch control circuit receives the output signal of timer 1 and the impedance detection result, both of which are in a valid state, the switch control circuit receives the output signal of timer 1 and the impedance detection result. When there is no AC input voltage, the emergency lighting control circuit controls the battery not to supply power to the emergency lighting lamp according to the impedance detection result. If the impedance detection result is a high impedance state and the emergency lighting does not need to be started, the battery is controlled not to supply power to the emergency lighting lamp. If the impedance detection result is a low impedance state, it indicates that a power outage has occurred and the emergency lighting needs to be started, the battery is controlled to supply power to the emergency lighting lamp. Then the first switch tube S1 is controlled to be turned on, and the battery supplies power to the lighting lamp. The switch S1 is used to connect the battery and the emergency lighting lamp load. The switch control circuit includes an AND gate, a trigger, a switch drive circuit and a sampling circuit. When the AND gate receives the comparison result and the impedance detection result, both of which are in a valid state, it outputs a high-level valid signal. The trigger generates a trigger signal to the switch drive circuit to control the switch S1 to be turned on, and the battery supplies power to the emergency lighting load. The sampling circuit feeds back the current size of the battery supplying power to the emergency lighting lamp.

[0037] refer to Figure 5 The high-voltage isolation circuit is connected between the AC input terminal and the battery. When there is an AC input, it is used to isolate the connection between the AC input terminal and the battery. The high-voltage isolation circuit includes an isolation switch. The isolation switch is controlled to be on and off according to the comparison result of the AC input detection circuit. When the comparison result indicates that there is no AC input voltage, the isolation switch is turned on. The high-voltage isolation circuit can also be a diode, which can also isolate the high-voltage input terminal and the battery.

[0038] refer to Figure 3, is a circuit block diagram of the third embodiment of the emergency lighting circuit according to the present invention. The emergency lighting control circuit in this embodiment is the same as the impedance detection circuit, switch module, and high-voltage isolation module in the first embodiment, and will not be repeated here. The difference is that in this example, the discharge circuit is connected to the end point of the lighting load to discharge the connection node voltage. The emergency lighting control circuit includes an impedance detection circuit, a comparison circuit, a switch control circuit, and a first switch tube. The impedance detection circuit obtains an input detection signal according to an input end connected to the AC input, and compares the input detection signal with a second threshold voltage to obtain the impedance detection result. The comparison circuit compares the connection node voltage between the discharge circuit and the lighting load and a reference voltage to obtain a comparison signal. Here, the reference voltage is the working voltage of the connected lighting load. The switch control circuit receives the comparison result of the comparison signal and the impedance detection result. When both are in a valid state, the first switch tube is controlled to be turned on so that the battery supplies power to the lighting lamp. Here, the lighting load may include multiple lamp beads, and the connected lighting load may be a partial load of the lighting load. In this example, the discharge circuit can be a set small current source, which pulls down the connected load voltage with a small current. When there is no AC input voltage, the voltage at the connection node between the discharge circuit and the lighting load is less than the reference voltage. When there is an AC input voltage, the voltage at the connection node between the discharge circuit and the lighting load is consistent with the reference voltage. When there is no AC input voltage but only residual voltage, the voltage at the connection node between the discharge circuit and the lighting load will also be less than the reference voltage. Therefore, it can be accurately determined whether there is an AC input voltage, thereby accurately starting the emergency lighting.

[0039] The present application also provides a lighting system, comprising the emergency lighting circuit and a lighting load, wherein the emergency lighting circuit receives an AC input voltage to control normal lighting and emergency lighting of the lighting.

[0040] The lighting system of the present application discharges the voltage at the AC input end or the voltage of the load in a discharge circuit. In special circumstances, such as when the AC input in an elevator is actually disconnected, the discharge circuit discharges the residual voltage of the AC input so that the system can accurately determine whether there is an AC input. In the absence of AC input, the emergency lighting is started by the built-in battery to ensure that the emergency lighting can be turned on smoothly in some specific occasions.

[0041] It should be noted that the specific implementation and corresponding illustrations given are merely a way of describing the implementation method of the present invention, and do not limit the specific structure of the implementation scheme of the present invention. Various changes or modifications can be made to these implementation schemes without departing from the principle and essence of the present invention, but these changes and modifications fall within the scope of protection of the present invention.

[0042] Although the embodiments are described and illustrated separately above, some common technologies are involved. It is the opinion of ordinary technicians in this field that the embodiments can be replaced and integrated. If the content is not clearly recorded in one of the embodiments, reference can be made to another recorded embodiment.

[0043] The above-described implementation methods do not constitute a limitation on the protection scope of the technical solution. Any modification, equivalent replacement and improvement made within the spirit and principle of the above-described implementation methods shall be included in the protection scope of the technical solution.

Claims

1. An emergency lighting circuit, wherein an AC input voltage supplies power to a lighting load through a power supply device, characterized in that: include, The power supply device includes a voltage conversion circuit and a battery. The voltage conversion circuit receives the AC input voltage to power the lighting lamp and charge the battery. The emergency lighting control circuit controls the battery to supply power to the emergency lighting when the emergency lighting is required to maintain lighting in the absence of AC input voltage, wherein the lighting load includes the lighting lamp and the emergency lighting. The emergency lighting control circuit includes a discharge circuit, which is connected to the input end of the AC input voltage or the end point of the lighting load to discharge the voltage of the connection node so that the emergency lighting control circuit can determine whether there is an AC input voltage. The discharge circuit is connected to at least one input terminal of the AC input voltage to discharge the voltage of the input terminal. The emergency lighting control circuit includes an AC input detection circuit, The AC input detection circuit is connected to an input end of the AC input voltage to obtain an input detection signal, and compares the input detection signal with a first threshold voltage. When the input detection signal is lower than the first threshold voltage, the discharge circuit is controlled to discharge the voltage at the input end of the AC input voltage.

2. The emergency lighting circuit according to claim 1, characterized in that: The discharge circuit discharges the voltage at the input end of the AC input voltage with a predetermined current.

3. The emergency lighting circuit according to claim 1, characterized in that: When the input detection signal is higher than the first threshold voltage, the discharge circuit is controlled to stop discharging the voltage at the input end of the AC input voltage. At the same time, after a delay period, a timer starts timing, and when the input detection signal is lower than the first threshold voltage or the timer reaches a preset value, the discharge circuit is controlled to discharge the voltage at the input end of the AC input voltage.

4. The emergency lighting circuit according to claim 1, characterized in that: The discharge circuit includes a first discharge circuit and a second discharge circuit, The first discharge circuit is connected to an input end of the AC input voltage, The second discharge circuit is connected to the other input end of the AC input voltage.

5. The emergency lighting circuit according to claim 4, characterized in that: The first discharge circuit includes any one of a switch tube, a resistor and a switch tube connected in series, and a switch tube and a current source connected in series; The second discharge circuit includes any one of a switch tube, a resistor and a switch tube connected in series, and a switch tube and a current source connected in series.

6. The emergency lighting circuit according to claim 4, characterized in that: The first discharge circuit includes any one of a resistor and a current source; The second discharge circuit includes any one of a resistor and a current source.

7. The emergency lighting circuit according to claim 1, characterized in that: The power supply device further includes a high voltage isolation circuit, and the emergency lighting control circuit includes an impedance detection circuit. The high-voltage isolation circuit is connected between the AC input terminal and the battery, and is used to isolate the AC input terminal and the battery when there is AC input. The impedance detection circuit is used to detect the impedance of the two AC input terminals to generate an impedance detection result. In the absence of an AC input voltage, the emergency lighting control circuit determines whether to start the battery to supply power to the emergency lighting lamp according to the impedance detection result.

8. The emergency lighting circuit according to claim 7, characterized in that: The impedance detection circuit obtains an input detection signal by connecting an input terminal of the AC input voltage, and compares the input detection signal with a second threshold voltage to obtain the impedance detection result. The emergency lighting control circuit includes a switch control circuit and a first switch tube. The switch control circuit receives a comparison result of the AC input detection circuit and the impedance detection result. When both are in a valid state, the first switch tube is controlled to be turned on so that the battery can power the lighting lamp.

9. The emergency lighting circuit according to claim 1, characterized in that: The discharge circuit is connected to the end point of the lighting load to discharge the connection node voltage. The emergency lighting control circuit includes an impedance detection circuit, a comparison circuit, a switch control circuit and a first switch tube. The impedance detection circuit obtains an input detection signal by connecting an input terminal of the AC input voltage, and compares the input detection signal with a second threshold voltage to obtain an impedance detection result. The comparison circuit compares the voltage at the connection node between the discharge circuit and the lighting load with a reference voltage to obtain a comparison signal. The switch control circuit receives a comparison result of the comparison signal and the impedance detection result, and when both are in a valid state, controls the first switch tube to be turned on so that the battery supplies power to the lighting lamp.

10. A lighting system, characterized in that: The emergency lighting circuit and lighting load according to any one of claims 1 to 9 are included. The emergency lighting circuit receives an AC input voltage to control normal lighting and emergency lighting of the lighting load.

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